Systematics and diversification of the Ichthyomyini (Cricetidae, Sigmodontinae) revisited: evidence from molecular, morphological, and combined approaches
Jorge Salazar-Bravo,
Nicolás Tinoco,
Horacio Zeballos,
Jorge Brito,
Daniela Arenas-Viveros,
David Marín-C,
José Daniel Ramírez-Fernández,
Alexandre R. Percequillo,
Thomas E. Lee, Jr.,
Sergio Solari,
Javier Colmenares-Pinzon,
Carlos Nivelo,
Bernal Rodríguez Herrera,
William Merino,
Cesar E. Medina,
Oscar Murillo-García,
Ulyses F.J. Pardiñas
Affiliations
Jorge Salazar-Bravo
Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States
Nicolás Tinoco
Museo de Zoología Escuela de Ciencias Biológicas, Pontificia Universidad Católica del Ecuador, Quito, Ecuador
Horacio Zeballos
Universidad Católica de Santa María, Arequipa, Peru
Jorge Brito
Instituto Nacional de Biodiversidad, Quito, Ecuador
Daniela Arenas-Viveros
Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States
David Marín-C
Colección Teriológica, Universidad de Antioquia, Medellin, Colombia
José Daniel Ramírez-Fernández
Skuë’ Conservation, Costa Rica Wildlife Foundation, San José, Costa Rica
Alexandre R. Percequillo
Escola Superior de Agricultura “Luiz de Queiroz”, Departamento de Ciências Biológicas, Universidade de São Paulo, Piracicaba, São Paulo, Brazil
Thomas E. Lee, Jr.
Department of Biology, Abilene Christian University, Abilene, Texas, United States
Sergio Solari
Instituto de Biología, Universidad de Antioquia, Medellin, Antioquia, Colombia
Javier Colmenares-Pinzon
Department of Biological Sciences, Texas Tech University, Lubbock, Texas, United States
Carlos Nivelo
Museo de Zoologia, Escuela de Biología, Universidad del Azuay, Cuenca, Ecuador
Bernal Rodríguez Herrera
Escuela de Biología, Universidad de Costa Rica, San José, San José, Costa Rica
William Merino
Escuela de Biología, Universidad de El Salvador, San Salvador, San Salvador, El Salvador
Cesar E. Medina
Museo de Historia Natural, Universidad Nacional de San Agustin, Arequipa, Arequipa, Peru
Oscar Murillo-García
Departamento de Biología, Universidad del Valle, Cali, Valle del Cauca, Colombia
Ulyses F.J. Pardiñas
Instituto Nacional de Biodiversidad, Quito, Ecuador
Ichthyomyini, a morphologically distinctive group of Neotropical cricetid rodents, lacks an integrative study of its systematics and biogeography. Since this tribe is a crucial element of the Sigmodontinae, the most speciose subfamily of the Cricetidae, we conducted a study that includes most of its recognized diversity (five genera and 19 species distributed from southern Mexico to northern Bolivia). For this report we analyzed a combined matrix composed of four molecular markers (RBP3, GHR, RAG1, Cytb) and 56 morphological traits, the latter including 15 external, 14 cranial, 19 dental, five soft-anatomical and three postcranial features. A variety of results were obtained, some of which are inconsistent with the currently accepted classification and understanding of the tribe. Ichthyomyini is retrieved as monophyletic, and it is divided into two main clades that are here recognized as subtribes: one to contain the genus Anotomys and the other composed by the remaining genera. Neusticomys (as currently recognized) was found to consist of two well supported clades, one of which corresponds to the original concept of Daptomys. Accordingly, we propose the resurrection of the latter as a valid genus to include several species from low to middle elevations and restrict Neusticomys to several highland forms. Numerous other revisions are necessary to reconcile the alpha taxonomy of ichthyomyines with our phylogenetic results, including placement of the Cajas Plateau water rat (formerly Chibchanomys orcesi) in the genus Neusticomys (sensu stricto), and the recognition of at least two new species (one in Neusticomys, one in Daptomys). Additional work is necessary to confirm other unanticipated results, such as the non-monophyletic nature of Rheomys and the presence of a possible new genus and species from Peru. Our results also suggest that ichthyomyines are one of the main Andean radiations of sigmodontine cricetids, with an evolutionary history dating to the Late Miocene and subsequent cladogenesis during the Pleistocene.
